The present application claims priority to Japanese Application No. P10-234659 filed Aug. 20, 1998, which application is incorporated herein by reference to the extent permitted by law.
1. Field of the Invention
This invention relates to a parallax image string pickup apparatus to be used for picking up parallax images of a scene from a plurality of different viewing angles.
2. Description of the Related Art
A holographic stereogram is produced as a result of sequential exposure and recording operations conducted for a large-number of original pictures obtained by photographically shooting an object from so many different viewing angles so as to record them as strip-shaped or dot-shaped element holograms on a recording medium. When the viewer watches a holographic stereogram with one of his or her eyes from a specific angle, he or she recognizes only a two-dimensional image that is a collection of pieces of information on part of each of the element holograms. When the viewer watches the holographic stereogram from another angle that is on the level of the first viewing angle, he or she then recognizes another two-dimensional image that is a different collection of pieces of information on part of each of the element holograms. However, when the viewer watches the holographic stereogram with both of his or her eyes, the recorded pictures are perceived by him or her as a three-dimensional image. A holographic stereogram as described above is normally prepared by means of holographic stereogram preparing apparatus 100 as shown in FIG. 1A of the accompanying drawings. Referring to FIG. 1A, the holographic stereogram preparing apparatus 100 comprises a laser source 101 adapted to emit a laser beam L1 showing a single wavelength and an enhanced level of coherence, a half mirror 102 for dividing the emitted laser beam L10 into an object beam L11 and a reference beam L12, optical parts 103 through 107 and display device 107 operating an optical system for the object beam L11 and a hologram recording medium 112 on which both the object beam L11 and the reference beam L12 are converged. It may additionally comprise an electrically driven stage 113.
The optical system of the object beam L11 specifically includes a total reflection mirror 103, a first cylindrical lens 104 for one-dimensionally diffusing the object beam L11, a collimator lens 105 for collimating the diffused object beam L11, a projector lens 106 and a second cylindrical lens 107 for leading the object beam L11 to the hologram recording medium 112 of/recording section P100. The above listed optical components are arranged in the above mentioned order along the optical axis of the object beam L11. The display device 108 comprises a transmission type liquid crystal panel arranged between the collimator lens 105 and the projection lens 106. As will be described hereinafter, the display device 108 is adapted to display an image formed on the basis of image data output from an image processing section (not shown).
The optical system of the reference beam 12 specifically comprises a cylindrical lens 109 for one-dimensionally diffusing the reference beam L12, a collimator lens 110 for collimating the diffused reference beam L12 and a total reflection mirror 111 for reflecting the reference beam L12 and leading it to the hologram recording medium 112. The above listed optical components are arranged in the above mentioned order along the optical axis of the reference beam L12.
The hologram recording medium 112 is typically a photosensitive film and, as shown in FIG. 1B, held to the electrically driven stage 113 so that it is intermittently driven to move in the direction of arrow c in FIG. 1B by the electrically driven stage 113.
As described above and shown in FIG. 1A, the laser beam L10 is emitted from the laser sourced 101 to strike the half mirror 102, where it is divided into the object beam L11 and the reference beam L12.
The object beam L11 is then made to enter the display device 108 by way of the cylindrical lens 104 and the collimator lens 105 and then, as it is transmitted through the display device 108, it is modulated according to the element image being displayed there. The modulated object beam L11 is then led to the hologram recording medium 112 located in the/recording section P100 by way of the projection lens 109 and the cylindrical lens 107. On the other hand, the reference beam L12 is led to the hologram recording medium 112 located in the/recording section P100 by way of the cylindrical lens 109, the collimator lens 110 and the total reflection lens 111.
Thus, the interference fringes generated as a result of interference of the object beam L11 modulated by the image displayed on the display device 108 and the reference beam L12 are sequentially exposed to light and recorded on the hologram recording medium 112 as strip-shaped or dot-shaped element holograms.
As described above, the image displayed on the display device 108 is formed from the image data output from the image processing section (not shown). The image is obtained by sequentially shooting an object from different angles by means of a parallax image string pickup apparatus (not shown) and appropriately processing the obtained images. The parallax image string pickup apparatus may comprise a single camera provided with a CCD (charge coupled device) and adapted to move one-dimensionally to shoot an object or a plurality of digital steel cameras adapted to shoot an object simultaneously.
A holographic stereogram is produced not necessarily from a single parallax image string but from parallax image strings obtained through a synthetic process using different pictures as disclosed in Japanese Patent Application Laid-Open No. 10-78742.
However, with a known parallax image string pickup apparatus having a configuration as described above, the camera unit for shooting an object is visible from the object, that may be a living person, so that the person being shot can become nervous about the operation of the camera. Additionally, such a known parallax image string pickup apparatus is not provided with a viewing target for attracting the gaze of the person being shot.
Therefore, when shooting a person with such a known parallax image string pickup apparatus, the gaze of the person being shot is often unstable and unnecessarily moving to consequently damage the effect of the obtained picture.
When shooting a person with such a known parallax image string pickup apparatus, it is desirable that the shooting conditions selected for shooting the person such as the position within the frame of the viewfinder are knowable to the person in order to make the produced holographic stereogram meet the demand of the person.
Particularly when the picture obtained by shooting a person with a parallax image string pickup apparatus is synthetically combined with another picture to produce a holographic stereogram, it is desirable that the person can imagine the final image that is produced by the picture synthesis.
In view of these circumstances, it is therefore the object of the present invention to provide a parallax image string pickup apparatus that can attract the gaze of the person being shot to make it stable without making the person nervous about the camera operation when the person is shot from a plurality of different angles and, at the same time, provide the person with necessary information including the position of the person in the frame of the viewfinder and other shooting conditions.
According to the present invention, the above object is achieved by providing a parallax image string pickup apparatus adapted to generate a parallax image string by shooting an object from a plurality of different angles, said apparatus comprising:
an image pickup means for picking up parallax images of the object; and
a cover-up means to be arranged between the object and the image pickup means for covering up the image pickup means.
With a parallax image string pickup apparatus according to the invention and having the above described configuration, parallax images of the object are picked up by the image pickup means while the latter is hidden and not visible from the object. Thus, since a parallax image string pickup apparatus according to the invention is practically not visible from the object when the latter is being shot, the latter may not be aware of the image pickup means and hence would not unnecessarily move to damage the effect of the picture that will be finally produced.
Preferably, said cover-up means includes a half mirror or a total reflection mirror and an image of the object is produced on the half mirror or the total reflection mirror, whichever appropriate.
With the above arrangement, when the object is a living person, the gaze of the person being shot will be attracted by the image of his- or herself produced on the cover-up means and hence stabilized. At the same time, the position in the frame of the viewfinder of the camera of the parallax image string pickup apparatus and other shooting conditions are knowable to the person when the latter is being shot.
Thus, with a parallax image string pickup apparatus according to the invention, the image pickup means is practically not visible from the object that is a living person when the latter is being shot and hence the person will not be aware of the image pickup means. Additionally, with a parallax image string pickup apparatus according to the invention, the gaze of the person being shot would not unnecessarily move so that a good parallax image string will be obtained to prepare a holographic stereogram.
On the other hand, with a parallax image string pickup apparatus according to the invention, the cover-up means produces an image of the person being shot so that the person may be able to know the position in the frame of the viewfinder of the camera of the parallax image string pickup apparatus and other shooting conditions if his or her gaze is stabilized.
Additionally, with a parallax image string pickup apparatus according to the invention, the person being shot can imagine the final image of the holographic stereogram that is produced by picture synthesis if the obtained images are synthetically combined with other images.
Thus, a parallax image string pickup apparatus according to the invention can effectively eliminate undesirable accidents such as unnecessary motions on the part of the object to produce a high quality parallax image string.